1. Field of the Invention
This invention relates to automotive air conditioning systems. More particularly, this invention relates to an automotive air conditioning system utilizing environmentally safe gases as the working fluid.
2. Description of the Prior Art
U.S. Pat. No. 4,123,916 (Kreger) discloses an automotive heat pump comprising: a first closed refrigerant circuit having an evaporator in heat absorbing relationship with the engine cooling system and having a condenser exposed to air flowing through the passenger compartment, the first closed refrigerant system being effective to utilize the engine cooling system as a source of heat for the heating mode of the air conditioning system; a second closed refrigerant circuit having an evaporator exposed to air flowing through the passenger compartment and a condenser exposed to ambient air, the second closed refrigerant circuit utilizing the heat within the passenger compartment as a source of heat for extraction and thereby cooling the air; a compressor driven by the engine common to each of the circuits for pressurizing the refrigerant for conveyance to either of the condensers; and a control mechanism for selectively connecting the compressor with either of the circuits.
U.S. Pat. No. 4,180,984 (Cheilis) discloses cryogenic apparatus wherein the refrigerator has a reciprocable displacer, driven by a motor shaft, which must be coordinated with fluid control means to control the inlet and exhaust of high and low pressure fluid, respectively, to produce cooling; and wherein the improvement comprises including means for providing proper coordination between displacer movement and fluid control means regardless of the direction in which the motor driven shaft is rotated. In an embodiment of a "Stirling" cycle apparatus, a motor acts as a mechanical drive means for a main drive shaft contained in a rotatable relationship by bearings. A compressor assembly consists primarily of a piston which is contained within a housing and sealed therein. The piston is driven in a reciprocable manner through a connecting link by a crankpin, which is attached to the main drive shaft. The crankpin has an extension which engages a raised shoulder on the end of a secondary shaft which is supported by bearings. The crankpin extension may engage either side of the raised shoulder to drive the displacer in a reciprocating manner via a crankpin, yoke, bearings and drive shaft. When the motor rotates the main drive shaft in a clockwise direction, the crankpin extension immediately abuts the shoulder to rotate the secondary shaft in the clockwise direction. The result is that the displacer is reciprocated about 90.degree. in advance of the movement of the compressor piston. However, if the main drive shaft were rotated in the counterclockwise direction for any reason, the crankpin extension would traverse approximately 270.degree. without abutting the shoulder and without causing the secondary drive shaft to rotate. At this point, the secondary drive shaft would be rotated in the counterclockwise direction and the displacer would still be driven 90.degree. in advance of the compressor piston.
U.S. Pat. No. 4,253,303 (Liljequist) discloses an engine incorporating the general principles of the "Stirling" cycle, comprising: a gas enclosure containing an entrapped gas, the gas enclosure including both a base portion and a power reciprocator, the gas enclosure defining internally thereof a variable volume expansion space and a variable volume compression space, flexible means sealingly connecting the base portion and the power reciprocator to minimize the escape of the entrapped gas between the base portion and the power reciprocation, yet allow relative movement therebetween; a displacer movably contained within the gas enclosure for moving the gaseous medium back and forth between the expansion space and the compression space; and an interconnection carried within the gas enclosure, connected to both the power reciprocator and the displacer, for interrelating the movement of the power reciprocator and the displacer in general accord with Stirling cycle characteristics.
U.S. Pat. No. 4,312,188 (Swenson, et al.) discloses an indoor space heating and cooling system, comprising: a refrigeration circuit having, in series relationship, a compressor and separate indoor and outdoor refrigeration circuit heat exchangers; a heat engine for driving the compressor while rejecting heat; a supplemental heat distribution circuit having indoor and outdoor rejected heat exchangers and means for conducting heat rejected from the heat engine to one or the other of the rejected heat exchangers; a first control means, in the refrigeration circuit, selectively settable to a cooling condition for directing refrigerant from the compressor through the outdoor and then through the indoor refrigeration circuit heat exchangers and back to the compressor or to a heating condition for directing refrigerant from the compressor through the indoor and then through the outdoor refrigeration circuit heat exchangers and back to the compressor; and a second control means, in the supplemental heat distribution circuit, selectively settable to a cooling condition for directing rejected heat from the heat engine to the outdoor rejected heat exchanger when the first control means is in its cooling condition or to a heating condition for directing rejected heat from the heat engine to the indoor rejected heat exchanger when the first control means is in its heating condition. The heat engine is of a type employing, throughout its cycle, a gas as its working fluid and wherein the working temperatures of the gas are substantially higher than the temperature desired to be maintained in the indoor space conditioned by the system. The heat engine may be a Rankine cycle engine or a non-Rankine cycle engine (e.g., a Stirling engine, an Otto engine, a Diesel engine or a Brayton engine).
U.S. Pat. 4,330,992 (Senft) discloses a drive mechanism for driving the displacer of a crank-type Stirling engine at the same frequency but out of phase with the power piston of the engine. A biasing means is linked to the displacer for applying a biasing force which urges the displacer in one direction of its reciprocation. A flexible band is secured to the displacer for applying a force opposite to the biasing force, with the other end of the band secured to an anchor which is mounted on another part of the apparatus and with the band extending slideably across at least one and preferably two bearing surfaces intermediate its secured ends.
U.S. Pat. No. 4,748,823 (Asano, et al.) discloses an automotive freezer-refrigerator system, comprising: a compressor driven by an automotive engine for compressing refrigerant; a freezing chamber having therein a freezing cold storage member having freezing cold storage material therein and a freezing evaporator in said chamber arranged outside and closely to the freezing cold storage member; a refrigeration chamber including a refrigeration cold storage member having therein refrigeration cold storage material higher in freezing temperature than the freezing cold storage member and a refrigeration evaporator in the refrigeration chamber arranged outside and in close contact with the refrigeration cold storage member; a valve means for controlling the flow of the refrigerant passing serially through the freezing evaporator and the refrigeration evaporator from the compressor so that the respective freezing and refrigeration evaporators are charged with a refrigerant at a substantially uniform pressure; a temperature sensor for detecting a temperature of the refrigeration chamber; and a control circuit for electrically controlling the operation of the valve means on the basis of a signal from the temperature sensor indicative of the temperature of the refrigeration chamber.
U.S. Pat. No. 4,796,430 (Malaker, et al.) discloses a cam drive for a cryogenic refrigerator, such as a modified Stirling cycle refrigerator, which is implemented either as a rotatable cylinder having a pair of circumferential camming grooves or as wobble plates having camming tracks on the periphery thereof. The cam drive unit drives the compressor and expander pistons of the refrigerator through cam followers.
U.S. Pat. No. 4,796,438 (Sato) discloses a method and apparatus for controlling an automotive air conditioning system which includes a temperature detecting sensor disposed in proximity to the air conditioning system, an acceleration detecting device for detecting acceleration of the automobile and a control unit. The control unit compares the detected air temperature with predetermined temperatures and controls the capacity of the compressor in accordance with the compared results and the acceleration condition of the automobile. The temperature in a compartment of the automobile can thus be controlled at a comfortable level and the power load imposed on the automobile engine can be reduced by operating the compressor at a reduced capacity.
U.S. Pat. No. 4,843,826 (Malaker) discloses a vehicle air conditioning system in which air or a working liquid is circulated through a heat exchanger mounted in intimate thermal contact with the cold head of a modified Stirling cycle refrigerator. The working liquid is circulated through a heat conductive tube to the location of the vehicle to be cooled. Second heat exchangers are connected to the tube at each of the locations and the air to be cooled is blown through the second heat exchangers. If air is circulated through the cold head mounted heat exchanger, the cooled air is ducted to the locations in the vehicle to be cooled.
The refrigerator is driven by an electrical motor and includes at least one compressor and expander piston pair driven by the motor. The refrigerator is encased in a hermetically sealed case whose interior is filled with a working gas which is preferably helium, although nitrogen can also be used.
Since the Stirling cycle refrigerator is electrically driven, there are relatively few restrictions on its placement in the vehicle. The electric power may be provided by a generator driven by the vehicle motor or the generator may be separately powered by an auxiliary motor.
U.S. Pat. No. 4,996,841 (Meijer, et al.) discloses a Stirling cycle heat pump for heating and cooling systems. The Stirling engine may be powered by direct heat input through combustor assemblies, a power take-off shaft can be provided to an external load such as an alternator or a generator; or may be powered by an electric induction motor as the prime mover; or may be driven by a pulley of an automotive internal combustion engine.
U.S. Pat. No. 5,094,083 (Horn, et al.) discloses a Stirling cycle air conditioning system which comprises a closed loop cooling system using a circulating coolant fluid as a heat transfer medium and includes a first heat exchange means for cooling a selected area, a means for circulating the coolant to the first heat exchanger and a Stirling cycle cooler having a second heat exchanger means for removing heat from the recirculating heat-laden coolant. The Stirling cycle cooler is hermetically sealed and employs an environmentally safe non-freon base coolant and has a magnetic clutch for coupling a pulley drive thereto. A first magnetic coupling magnetically couples shaft power of the driven pulley to a first end of a crankshaft of the Stirling cycle cooler through a first end wall of the hermetically sealed cooler. A second magnetic coupling magnetically couples a second end of the cooler crankshaft through a second end wall of the hermetically sealed cooler to an impeller pump for pumping the coolant through the closed loop system.